Title :
Linearity enhancement of a directly modulated uncooled DFB laser in a multi-channel wireless-over-fibre system
Author :
Ismail, Tawfik ; Mitchell, Jason E. ; Seeds, Alwyn J.
Author_Institution :
Dept. of Electron. & Electr. Eng., London Univ. Coll., UK
Abstract :
We present the first experimental demonstration of two 3.5 MSymb/s QPSK modulated wireless channels over fibre in a 2.2 km fibre ring architecture using feed-forward linearisation at the base station to improve the dynamic range of a directly modulated uncooled DFB laser. A reduction of 10 dB is observed in the spectral re-growth caused due to strong input from the adjacent channel together with reduction from 25% to <10% in the error vector magnitude at input level of -25 dBm of the weaker channel. Intermodulation distortion is reduced by 10 dB when two strong channels are at +12 dBm input level.
Keywords :
adjacent channel interference; distributed feedback lasers; feedforward; intermodulation distortion; optical modulation; quadrature phase shift keying; radio-over-fibre; 2.2 km; DFB laser modulation; error vector magnitude; feedforward linearisation; fibre ring architecture; intermodulation distortion; multi-channel wireless-over-fibre systems; optical communication; radio-over-fibre system; spectral re-growth; uncooled DFB laser; Feedforward systems; Fiber lasers; Intermodulation distortion; Laser noise; Linearity; Optical distortion; Optical fiber filters; Optical fibers; Optical filters; Optical transmitters;
Conference_Titel :
Microwave Symposium Digest, 2005 IEEE MTT-S International
Print_ISBN :
0-7803-8845-3
DOI :
10.1109/MWSYM.2005.1516506
